One Rep Max Calculator
Calculate your estimated one-rep max (1RM) for any lift using multiple formulas including Epley, Brzycki, and more.
Our One Rep Max Calculator estimates your maximum strength safely. Here's how to use it:
Step 1: Enter the weight you lifted.
Step 2: Enter the number of repetitions completed (1-15 reps for best accuracy).
Step 3: Select a formula or use 'Average' for a combined estimate.
Step 4: Click 'Calculate' to see: - Your estimated 1RM - Comparison across all major formulas - Training percentage chart with rep ranges - Purpose for each intensity zone
Common 1RM Formulas:
Epley: 1RM = Weight × (1 + Reps/30) Brzycki: 1RM = Weight × (36 / (37 - Reps)) Lombardi: 1RM = Weight × Reps^0.10 Mayhew: 1RM = (100 × Weight) / (52.2 + 41.9 × e^(-0.055 × Reps)) O'Conner: 1RM = Weight × (1 + 0.025 × Reps) Wathan: 1RM = (100 × Weight) / (48.8 + 53.8 × e^(-0.075 × Reps))
Training Intensity Zones: - 100%: 1 rep (Max testing) - 85-95%: 2-5 reps (Strength) - 75-85%: 6-8 reps (Power/Hypertrophy) - 65-75%: 9-12 reps (Hypertrophy) - 50-65%: 15+ reps (Endurance)
Verified Precise